Equity - Class of Stock Disclosures - Common Stock and Shelf Registrations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity
Proceeds from common stock issued, net of issuance costs			$ 1,005,000
Common Stock
Equity
Number of shares repurchased	76,574	45,030	31,326
Common Stock | Equity Distribution Agreements
Equity
Maximum offering capacity under shelf registration statement	$ 200,000,000	$ 200,000,000
Shares common stock sold	0		22,244
Proceeds from common stock issued, net of issuance costs			$ 1,005,000
Compensation paid to sales agents			18,000
Reclassification of accumulated costs to additional paid in capital			76,000
Amount available under effective shelf registration statement	$ 200,000,000		$ 184,139,000